The first question concerns what actually defines a ring. My plan was to make a library light source that would last indefinately but not require vis, so I invented this spell:
My question is, could the ring of this spell be traced onto the rim of a bowl? If the bowl was moved, but not broken, would the spell persist?
The second question involves a sword I was trying to design. I want this sword to be able to strike down demons that are in spirit form. I started designing the effect by taking Demons Eternal Oblivion and modifying it to a touch range, then I started running conceptual problems. Can a spirit even be affected by a touch range spell? Would a touch version of DEO with a Sun duration continue to sap might every time it struck, or only the first time?
If that version doesnt work Im thinking that maybe a version of DEO with personal range and momentary duration would work by draining the demon if it occupies the same space as the sword. If this works I could add unlimited uses per day and have it trigger every moment. However, Im not sure if personal range would work as intended or just continually attempt to drain infernal might from the sword itself.
There's absolutely no reason you couldn't use the rim of a bowl as your circle. Unfortunately, I do believe there's a rule that you can't move a circle (Noble's Parma) though you could of course just cast the spell again after the move.
There exist sample spells where people use 'Touch' to target spirits (or vice versa) so the Touch range is certainly appropriate. The tricky part is seeing and targeting the spirit in the first place.
I'd design the spell with Momentary duration and then spend the 10 levels to give Unlimited uses/day. Also, since the item targets Spirits exclusively, don't forget to buy as much Penetration as you can manage even if it means reducing the amount of Might you're able to drain from the target.
I don't believe moving is an issue. There has been some discussion as to what constitutes physically breaking the ring. Is it something crossing the ring or is it actually making a gap in the ring.
The key with DEO or other variants is to consider penetration, as Gremlin indicated. Unless the character is a Verditius or can't cast spells, spells are probably better. Consider making a talisman, eventually with a component that can hurt damage demons. Don't forget the SM bonus is limited to your magic theory, do red corral probably isn't worth it.
I think items of quality can have more space. Look at the verdi section. Also, you can pass over this one by having more expensive materials engraved in the sword, so the sword is a media to transfer the effect stored in say a diamond in the criss of the sword. Having the sword be a talisman also helps with such space issues.
Base 2 is only candle level light, which is really not much. Not what I would call a great light source for libraries unless you are ready to cast it a dozen times. If you can afford to, going up to Base 3 (torchlight) or better yet 4 (cloudy day) would really make this spell great for libraries. It would also change it to a CrIg(Im) spell (Imaginem becomes the requisite), not that that matters much.
Interesting. Since I need 6 spaces for the effects, I could just add a tiny piece of silver to the pommel and reduce the total cost of the device down to 12 vis with a minimum Magic Theory of 3. Certainly a lot more manageable.
The work would be spread over 3 seasons. First season would open the device for 6 vis, second season would instill the first effect for 3 vis, third season would instill the second effect for 3 vis. Once I had lab notes and a lab total of at least 60, additional swords could be made in two seasons, one to open with 6 vis and one to instill both effects, since they are both PeVi. Unless Im misreading something it would always take at least two seasons to complete, since opening is a separate step.
Yes, your right.
For Demons it isn't an issue, you don't want their Vis. Really, you don't. But for magic creatures, it's generally accepted that if you kill a being with a might stripper it won't leave any Vis. I can't recall if it is a common HR or explicitly stated somewhere. I'm away from easy access toy books.
I'm toying with an offensive ReVi spell that rips the Vis out of a still-living (as it were) supernatural creature. Same end effect as a dead creature, but you can essentially render it down WHILE you attack, rather than afterwards. Unfortunately, I'm not quite sure what the guideline would be.
My thought is that it would be some variation of the ReVi effect that moves the vis to a specific part of the body, and then uses PeVi (with a T: Part) to tear that piece of the body off.
All of which would have to penetrate Magic Might, of course.
Check RoP:I, Ablation. It is what you are planning to do from a hermetic perspective. You might get some inspiration there.
I think you are right about the spell tecniques. You could probable come away with Rego, muto and creo alternatives to separate the bits with vis from the creature, though.
What I am less sure is that you can do it without killing the creature. It is heavy torture, after all, where you are bleeding the creature and the consequences are likely to be fatal. That vis is part of its essential nature after all. I guess your magus does not care about this in the first place, but just to be sure
Yup. This is basically in answer to the issue of the Rego Vim specialist going out monster hunting. While X's Eternal Oblivion will probably be more efficient at direct-kills, he'd rather have some useable vis at the end.